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Questions tagged [bioenergetics]

The study of energy and its transformations as it pertains to living systems in the context of biochemistry.

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CO$_2$ in photorespiration

"Photorespiration is wasteful to plants as it reduces the amount of CO$_2$ available for fixation" my textbook says. But we also know that photorespiration takes place when the concentration ...
Spluesh's user avatar
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How is the Gibbs Free energy of Redox reaction during Electron transport of the Mitochondria utilized to pump protons across mitochondial membrane?

I understand basics of the electron transport chain..that electrons "donated" from NADH and FADH2 moves through redox centers within respiratory complexes I, III, and IV (II is not ...
Sanjay Biswas's user avatar
5 votes
2 answers
691 views

Which cells in our body perform lactic acid fermentation?

Does lactic acid fermentation in humans happen only in the muscle? I have read in this Wikipedia page that human muscle cells sometimes respire anaerobically to produce ATP and lactic acid. Does it ...
Patrick's user avatar
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What happens exactly in the electron transport chain when there's no oxygen

what is the mechanism of hypoxia in the electron transport chain? It stops because there's no terminal electron acceptor so the IV complex become "stuck" with an electron? There's no other ...
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Is Chemiosmosis a hypothesis or a theory?

I was trying to find out whether chemiosmosis is a hypothesis or a theory. Naturally, I first searched on Wikipedia, but the article on chemiosmosis uses both the words, which is confusing. The ...
Aditya Kumar Panda's user avatar
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1 answer
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Why is hydrogen to oxygen ratio used to compare energy storage efficiency?

I came across an article that says that lipids are more efficient energy storage molecules compared to starch because lipids have higher “hydrogen to oxygen ratio”. I do not understand how “hydrogen ...
green onion's user avatar
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What is the latest estimated probability for the self assembly of a primitive cell? [closed]

Peusner (Concepts in Bioenergetics, 1974) estimated the probability of the self-assembly of a primitive cell as $10^{-254}$. Given how much more we now know about cell biology, what is the latest ...
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Do ATP generated aerobically and anaerobically have different phosphorylation potentials?

We have recently postulated that ATP generated by substrate-level phosphorylation may have a different phosphorylation potential to the ATP generated by oxidative phosphorylation. This could be ...
Mansi El-Mansi's user avatar
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What are the roles of ATP and ADP in muscle contraction?

I've always known that the hydrolysis of ATP generates ADP, P, and energy, so I'd assume that if energy is necessary in a given process, ATP hydrolysis should occur (or another exothermic process). ...
Enlico's user avatar
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Which enzymes use ATP?

It is well known that there are many enzymes which use ATP in their function, and any enzyme that work against an energy gradient need to have that energy supplied from somewhere, but just as well ...
Anthony Khodanian's user avatar
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How do cellular conditions change the Gibbs free energy of a reaction?

How do cellular conditions change the Gibbs free energy of a reaction? Taking glycolysis as an example, how exactly would cellular conditions affect the free energy released from this reaction?
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How many Watt-hours can an electric eel produce in a day?

Electric eels are cited as being about to produce about 860 watts of energy. But I haven't been able to find information on how long they can sustain their charge. https://www.youtube.com/watch?v=...
Johnny's user avatar
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What is the energetic costs in KJ/g NH3 for nitrogenase fixation

What is the energetic costs in KJ/g NH3 for nitrogenase fixation. I want to compare Haber-Bosch vs nitrogenase. How would I force the biological stochiometry of 8e- electrons into an energy quantity. $...
dlight's user avatar
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How does the light-independent stage of photosynthesis get H+ ions?

From what I understand from my grade 11 biology: During the light-dependent stage of photosynthesis, water molecules split, producing hydrogen and oxygen atoms. The oxygen atoms are basically “waste ...
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2 answers
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What determines whether a reaction using ATP produces ADP or AMP?

Most reactions using ATP seem to involve: ATP → ADP + Pi but in some the reaction is ATP → AMP + PPi followed by hydrolysis of the pyrophosphate: PPi → 2Pi Is there any principle that determines which ...
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Activated carrier molecules and their relationship to enzymes

I am reading Molecular Biology of the Cell, and one thing I don't quite get is the difference between an enzyme and an activated carrier molecule. I understand that enzymes lower the activation energy ...
An Ignorant Wanderer's user avatar
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Under which conditions is human energy consumption minimized?

Including but not limited to: body state consumed food composition state of the digestive tract diseases wounds sleep coma, etc.; death excluded environment state temperature light pressure, etc. ...
Captain Trojan's user avatar
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About the mechanism of coupled reaction/metabolism with ATP

I am not in the field of biochemistry so this may be a rookie question or misconception. I heard occasionally about the energy "released" from ATP hydrolysis fueling (endergonic) biological reactions....
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Why does atrazine kill photosynthetic bacteria and not nonphotosynthetic bacteria?

Atrazine was found to bind to Qb, which is involved in electron transport to create ATP in photosynthetic bacteria. Why does this herbicide kill photosynthetic bacteria, while having little to no ...
user16949's user avatar
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Bioenergetics book

I already asked this question on the physics SE but redirected here: In the field of biophysics, it seems there is a subfield called "bioenergetics" about the processes of generating energy by ...
PackSciences's user avatar
2 votes
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ATP and Muscle Contraction

I have a question regarding how molecular interactions manifest in physical actions - such as hanging from a bar. To the best of my understanding, when it comes to the contraction of muscles, ATP is ...
Shayan Hemmati's user avatar
3 votes
1 answer
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Cellular respiration in carnivorous animals

What is the equation for cellular respiration in carnivores as they don’t consume carbohydrates to break down into glucose in the following manner: Glucose + oxygen -> water + CO2 +energy. Do they (...
TheSprintingEngineer's user avatar
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What are the (evolutionary) advantages of secondary transport?

Secondary active transport uses electrochemical gradients as a source of energy for the uphill transport of substrates (coupled to downhill transport of the ion). However except for in a few cases (e....
Mirte's user avatar
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How are electrons entering the electron transport chain in cellular respiration energised (excited)?

In photosynthesis, electrons are excited by light energy from the sun (photoactivated). How do they become excited in human cellular respiration? I believe it has something to do with NADH and ...
Hydro Gen's user avatar
1 vote
1 answer
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Fuel from photosynthesis

I was reading how plants make use of sunlight, CO2 and some other stuff to make energy. So why can't we create artificially engineered bio solar panels which will take sunlight, C02, water and other ...
vishal's user avatar
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What are the limiting factors of human stamina?

What are the limiting factors of (human) stamina? Let's define stamina as the capacity to continue doing a physical activity. We clearly have our limits, so what aspects of physiology impose a limit ...
JustSnilloc's user avatar
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3 answers
110 views

Could a mammal convert ingested dissolved CO2 to usable energy?

I'm trying to find out if it's possible that a mammal could orally ingest dissolved CO2 and convert it to energy for body heat, organ function, etc. Unfortunately, most of the scientific sources I've ...
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Recent research in bioluminescence powering photosynthesis?

In 2013 there was a Chinese study published on "Bioluminescence as a light source for photosynthesis," which is briefly summarized in this Chemistry World article. There was a question on Biology.SE ...
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334 views

What is the primary energy source for sprouting plants?

To what extent are young plants powered by the potential energy stored in the seeds and when does solar energy take over? Are there other energy sources involved? I was observing sprouts in a ...
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1 answer
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Negative Oxygen Consumption Rate

Oxygen consumption rate (OCR) is defined as the rate at which cells consume oxygen. I reason that for cells not capable of photosynthesis, OCR is strictly non-negative. That was until I read this ...
Jonathan Smith's user avatar
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1 answer
948 views

Can the Na+/K+ pump backwards to generate ATP?

The standard physiological direction of the Na+/K+ pump is to export 3 Na+, import 2 K+, and hydrolyze one ATP to ADP. Can it be driven backwards, importing 3 Na+, exporting 2 K+, and generating ATP? ...
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ATP stoichiometry of the Na+/K+ pump

The Na+/K+ ATPase pump exports 3 Na+ for every 2 Ka+ imported. This process is ATP dependent, but I have not been able to find how many ATPs are required in each translocation. What is the ...
a06e's user avatar
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Does the energy from ATP hydrolysis vary among different cells?

I know that when ATP is hydrolyzed into ADP it gives 7.3 kcal/mol. The question is, does this value vary among different types of cells?
Reem M.Al Haj's user avatar
3 votes
0 answers
325 views

Affinity for oxygen and carbon dioxide in animals

I'm currently reading Treatise on Invertebrate Paleontology (A) and don't understand the following fragment: The affinity for oxygen in lower animals is many times that in higher ones, whereas ...
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Bioenergetics of bioconversions: is there a surplus of energy?

By bioconversion, I mean a microbial process during which resting cells are used in order to convert a substrate to a desired product, whithout cell growth. For example, in this paper, they used ...
Flo's user avatar
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12 votes
5 answers
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Are there known life forms that are able to transform mechanical energy into chemical energy?

Are there known life forms that are able to transform mechanical energy into chemical energy? This question asks a similar subject, but more specific and has no answers. The background of this ...
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4 votes
2 answers
3k views

Measuring the Rate of Photosynthesis

Update: I have just received a grant to pursue this research. However, I must still perform the preliminary experiment described below before dipping into my very limited funds. Thank you for any ...
Joe Smith's user avatar
1 vote
0 answers
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Energy cost of chewing vs production of enzymes

Consider a hypothetical case that you ingest a piece of starch. Which is more costly energetically 1) chewing + reduced amount of enzymes production needed or 2) sole production of all the enzymes for ...
y chung's user avatar
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Bioenergetics and equilibrium

"The living state is a non-equilibrium steady state to be able to perform work." I know that a "steady state" is the one in which the rate of energy gain is equal to rate of energy loss. Then how can ...
Shivanshu Siyanwal's user avatar
5 votes
1 answer
225 views

How do plants store energy by potassium battery?

Plants have a so-called potassium battery system for energy storage/conversation. Wikipedia only has a reference to a technical article. Can someone explain it in a layman's language (or refer to a ...
LiamHor's user avatar
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1 vote
1 answer
3k views

Is co-transport within a cell active or passive transport?

ATP is used to actively transport H+ out of the cell against the concentration gradient. The H+ & sucrose cotransporter, for example, then uses this proton gradient for transport. H+ goes back ...
Daniel Ip's user avatar
5 votes
1 answer
173 views

Organic battery?

Similar to the Matrix movie where humans were used as a source of electricity but different by using electric eels. Farmed like tuna what would be the electricity exchange to the food they eat?
Muze's user avatar
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3 votes
1 answer
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Location of t tubule in muscle

Why do mammalian skeletal muscles have t-tubules at the junction of the anisotropic and isotropic band, whereas non-mammalian muscles and cardiac muscles have it at Z-line? What could have been the ...
JM97's user avatar
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3 votes
2 answers
2k views

What does “energy transfer in cells” mean?

"ADP and ATP are involved in energy transfer in cells." I know what is ATP and I know how ADP is formed, but I don’t understand what “energy transfer in cells” means.
Sam19KY's user avatar
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Can the NADPH/NADP+ ratio affect the FMN to FMNH2 ratio in the complex I of the mitochondria?

This is the reaction: FMNH2 + NAD(P)+ <-> FMN + NAD(P)H + H+ The reaction works either with NADH/NAD+ or NADPH/NADP+ I know that the NADH/NAD+ ratio affects the FMN to FMNH2 ratio But does the ...
Konrad's user avatar
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How did scientists establish the reactions that occur in metabolism? [closed]

How did scientists establish that macromolecules like proteins, carbohydrates and lipids are synthesized from other molecules with intermediate products by living cells. Did they observe this under ...
Aafia's user avatar
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8 votes
3 answers
6k views

Do all prokaryotes have ATP synthases and an electron transport chain?

I was looking this up and I'm wondering if so far I'm correct about the following: For the most part eukaryotes do aerobic respiration, which involves glycolysis, the Krebs cycle and oxidative ...
Gabriel's user avatar
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Mechanism behind energy generation

I recently read about methanogens and methanotrophs. One converts CO2 to methane and vice versa respectively. I can't get exact mechanism for the methanotrophs and I know they can't be reversed ...
anamika Singh's user avatar
2 votes
1 answer
584 views

How many calories do gut bacteria burn?

It has become well-accepted that microbiota of the gut (a.k.a. gut bacteria) consume calories that are ingested and can have significant effects on energy metabolism in humans. For example, if you ...
Vance L Albaugh's user avatar
1 vote
1 answer
119 views

Conversion of ATP to NADH without creating a proton motive force?

Is it possible to convert ATP into NADH and vice versa without first creating a proton motive force? If so by what mechanism is it done?
Quantum spaghettification's user avatar